Elevators
Points and comments are a snapshot, not live.
Smarter elevator algorithms don't always reduce wait times; simple up/down buttons often outperform destination dispatch.
The article explains elevator dispatching algorithms, from simple SCAN/LOOK to smarter RSR (Relative System Response) and destination dispatch. It simulates wait-time distributions under different traffic patterns. RSR re-optimizes every 5 seconds and can outperform LOOK at moderate flow, but LOOK catches up at high flow or with few cars. Surprisingly, destination dispatch kiosks, which assign riders to specific cars before arrival, often yield worse wait times than traditional up/down buttons because they lose rebalancing flexibility.
The author provides an interactive simulation to explore trade-offs among floors, cars, and flow rates.
What commenters are saying
Commenters highlighted the elevator scheduling game elevatorsaga.com and shared war stories from real-world integrations. Several noted that building owners optimize for throughput and cap-ex, not passenger wait time, and that code regimes limit elevator manufacturers. A counterpoint: destination dispatch can help mobility-disabled riders if designed with wheelchair buttons. One commenter recalled that older buildings with sky lobbies and operators worked better than any smart system, and that vendors push smart solutions for profit, not performance.